Impellers for centrifugal pumps



Jan. 9, 1968 w. c. s E 3,362,338

IMPELLERS FOR CENTRIFUGAL PUMPS Filed Jan. 24, 1966 IIVI/EA/TDR WALTER(f/APPLE STETHEM ATTORNEYS United States Patent 3,362,338 IMPELLERS FORCENTRIFUGAL PUMPS Walter Chapple Stethem, Don Mills, Ontario, Canada,as-

signor to S. A. Armstrong Limited, Toronto, Ontario, Canada Filed Jan.24, 1966, Ser. No. 522,664 Claims priority, application Canada, Jan. 28,1965, 921,845 4 Claims. (Cl. 103-415) ABSTRACT OF THE DISCLOSURE Asingle or double stage inlet impeller for a centrifugal pump includestwo impeller elements in a back-to-back relationship, the two impellerelements being arranged on 1 This invention relates to an impeller foruse in centrifugal pumps and more particularly to an impeller element ofone-piece stamped construction.

An object of the invention is to provide an impeller which is eflicient,simple and economical to manufacture.

An impeller constructed in accordance with the invention comprises aone-piece disc having alternately protruding and recessed generallyradial folds which constitute fluid channels on both faces of the disc,each of the fluid channels being defined by a pair of opposed side wallsand a transverse wall, and the disc having a central openingintersecting the inner ends of the fluid channels to provide inlets forthe fluid channels.

Preferred embodiments of the invention are illustrated by way of examplein the accompanying drawings, in which:

FIG. 1 is a perspective view of an impeller element forming part of animpeller constructed in accordance with the invention;

FIG. 2 is a perspective view, partly broken away, of a single stage,single inlet impeller constructed in accordance with the invention andhaving a single impeller element;

FIG. 3 is an elevational view of the impeller of FIG. 2;

FIG. 4 is a perspective view, partly broken away, of a single stage,single inlet impeller constructed in accordance with the invention andhaving three impeller elements;

FIG. 5 is a perspective view, partly broken away, of a single stagedouble inlet impeller constructed in accordance with theinvention andhaving two impeller elements; and

FIG. 6 is a perspective view, partly broken away, of a two stageimpeller constructed in accordance with the invention and having twoimpeller elements.

Referring to FIG. 1, an impeller element 10 comprises a one-piece disc11 that is formed with alternately protruding and recessed generallyradial folds which constitute a set of fluid channels 12 on one face ofthe disc and another similar set of fluid channels 13 on the oppositeface of the disc. The fluid channels 12 are defined by side walls 14 andtransverse walls 15, and the fluid channels 13 are defined by the sidewalls 14 and transverse walls 16. The transverse walls 15 are coplanar,as are the transverse walls 16, and the two planes which respectivelycontain the transverse walls 15 and 16 are mutually parallel and aresubstantially perpendicular to the axis of rotation of the impeller. Theside walls 14 are substantially perpendicular to the transverse walls15, 16. A central opening 17 intersects the inner ends of the fluidchannels 12, 13 to provide a series of radially disposed inlets 18 ofgenerally rectangular shape. The side Walls 14 are curved and theydiverge outwardly from the inlets 18 in a spiral configuration toterminate at their outer ends at outlets 19 which are of considerablylarger area than the area of the inlets 18, so that fluid velocity headat the inlets 18 will be converted to fluid pressure head at the outlets19.

The impeller element 10 can be combined with a front plate 20- and aback plate 21 (see FIGS. 2 and 3) to provide a single stage, singleinlet impeller. The front plate 20 is secured to the transverse walls 15and it closes the fluid channels 13 except for their inlets and outlets;the front plate 20 has a central aperture 22 bounded by a cylindricalflange 23, and the aperture 22 communicates with all the inlets 18 toprovide a suction inlet for the impeller. The back plate 21 is securedto the transverse walls 16 and it closes the fluid channels 12 on theopposite face of the disc, except for their inlets and outlets; the backplate 21 is provided with a central hub 24 having a threaded bore 25 forattachment to a motor shaft (not shown).

FIGS. 4, 5 and 6 show various other forms of impellers having aplurality of impeller elements 10.

The impeller of FIG. 4 comprises three impeller elements that aresecured together back to back to provide fluid channels 26 of increasedcapacity, and it will be noted that the fluid channels 12 of one discare aligned with the fluid channels 13 of an adjacent disc. Like theimpeller of FIGS. 2 and 3, this assembly of impeller elements isprovided with a front plate 20 and a back plate 21. In a similar manner,other numbers of impeller elements can be combined together to providean impeller of the desired capacity.

A single stage double inlet impeller is shown in FIG. 5, and it includestwo impeller elements in a back to back relationship, the two impellerelements being arranged on opposite sides of a flat, circular centerplate 27. At both its opposite ends the assembly is provided with afront plate 20, and thus the impeller has two suction inlets eachcommunicating with the inlets of the impeller element (or elements) onthe near side of the center plate 27 but not with the impeller element(or elements) on the opposite side of the center plate 27. A central hub28 having a threaded bore 29 is provided on the center plate forattachment to a motor shaft. For balance, it is preferable to have thesame number of impeller elements on each side of the center plate.

All the above described impellers are of the single stage type. Anexample of double stage type is given in FIG. 6 which shows an impellerthat is substantially the same as the impeller shown in FIG. 5 exceptthat center plate 30 is of larger diameter than the impeller discs. Thehousing (not shown) within which the impeller is to be placed is soarranged that fluid which enters suction inlet 31 is expelled throughoutlets 32, flows around the center plate 30, thence through suctioninlet 33 on the opposite side of the center plate, eventually to beexpelled through the outlets on that side; the path of the fluid isindicated by a series of arrows.

The impeller elements can be formed from any material possessingsufficient strength and which is capable of being stamped or otherwiseconveniently formed, such as cold rolled steel, brass, stainless steeland aluminum. The various component parts of the impeller canconveniently be secured together by spotwelding, silver soldering orlike methods.

Although the impellers described herein are intended for use withrelatively incompressible fluids, such as water, it is to be understoodthat principles of the invention can be applied to impellers suitablefor use with compressible fluids, such as air.

What I claim as my invention is:

1. An impeller, a plurality of one-piece discs positioned coaxially,each disc having alternately protruding and recessed generally radialfolds which constitute fluid channels on both sides of the disc, each ofthe fluid channels being defined by a pair of opposed side walls and atransverse wall, and each disc having a central opening intersecting theinner ends of the fluid channels to provide inlets for the fluidchannels, a front plate secured to the outer face of one end disc toclose the fluid channels of said outer face except for their inlets andoutlets, said front face having a central aperture in communication withthe fluid channel inlets to provide a suction inlet for the impeller,and a back plate secured to the outer face of the opposite end disc toclose the fluid channels 20 of said outer face except for their inletsand outlets wherein the discs are arranged in two groups on either sideof a center plate so that the fluid channel inlets of each groupcommunicate with each other but not with those of the other group, andwherein the back plate has References Cited UNITED STATES PATENTS929,129 7/ 1909 Harder 230-434 2,486,619 11/ 1949 Truxler 230-134.452,802,620 8/1957 Darrah 230134 2,899,129 8/1959 Schwaiger 230-134FOREIGN PATENTS 192,822 12/ 1907 Ger-many. 368,563 2/ 1923 Germany.

419,252 11/ 1954 Great Britain.

HENRY F. RADUAZO, Primary Examiner.

